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b=G5nou7g3BqkL8GO0V7LH3FWiz4Xoa6UoLxbdYyBRNRvGCkLhqMbp6+wA6pS2p/wVK sidohVIkYNtujZDVfUM350+FJ1wgxX60ajONcjnohTOYKxjQMkWAyWELf0CnGvr02Q gjohG0PwgaN8nLfzWqbu/L7Nia0F7RUnlNp248cYN3q92WlLgwaMyITpAQqEehfXjP sea+oh86kMUv9RdeT7EsCS9ncjSttPEBd3y2ixsVo0icKtKNxWC3oeZh/c3Q5WQ0Sk EhQsd9nLHWTRG2SBKA3cDpqFKNSGHPTNptvc7RmnmGg5bTdKrg/s5hmD3gnBUMZB7v QtpTiEniK6sSg== Date: Sat, 3 Oct 2026 10:30:10 -0400 From: Sasha Levin To: "Lorenzo Stoakes (ARM)" Cc: rppt@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, david@kernel.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, regressions@lists.linux.dev, stable@vger.kernel.org, 4ncienth@gmail.com, alexander.motin@truenas.com, caleb.stjohn@truenas.com, ameer.hamza@truenas.com Subject: Re: [REGRESSION] secretmem: SIGBUS on memfd_secret() pages while perf record runs Message-ID: References: <20261002175651.811343-1-ameer.hamza@truenas.com> <2026-10-02-rc-reply-0003-re-secretmem-sigbus-perf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Stat-Signature: s8x1myin4kfqkgdbeyzcbp6cnyfgz9hk X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 7D7C24000E X-HE-Tag: 1791037813-849914 X-HE-Meta: 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 0vrBL4Gq DCg4UyP5X0f2HrUvlAWfmDS7/6g1kg/mH14pic7nwipBJ2MekOBo1W3cXkiDHjAOVI2C+nr+tIHqKBU745VvgLLzbqSy5elZxp9sox53vEmbM9Y33xwU0NML2G46JN2KF+JXxl/QxKlfsBbpHP3ZX4Uxlld4O3ryqmZhKQwYfnnwL2EP0xtXFw1PN+cpNkYl1sHZMBih4jNJUmGL4pzXtNgShnjsEe6gC6tCjgj4kucJVFJqjGQMoEiQqn4guzHAsEs16kKBDb8k8/Yw+M2QStnv++KhCIF2IZKuyTZW0DCMDLhQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Oct 03, 2026 at 10:18:34AM +0100, Lorenzo Stoakes (ARM) wrote: >On Fri, Oct 02, 2026 at 09:30:23PM -0400, Sasha Levin wrote: >> > Since commit 97d34aa65c29 ("mm/secretmem: properly account locked >> > pages"), in v7.3-rc2 and the 6.18.52 and 7.2.5 backports, touching a >> > memfd_secret() page for the first time fails with SIGBUS while the >> > same user is running perf record, and read() into such a page fails >> >> Thanks for the report. I've dropped 97d34aa65c29 from the 6.12 queue, >> and also removed the copies that were staged for 6.6 and 6.1. >> >> 7.2.y and 6.18.y already shipped it, so those need an upstream fix, >> which stable will pick up once it lands. > >Sasha, > >Could we perhaps take a breath and pause? I pulled this out quickly because I didn't want this issue to go into the kernels that were released this morning. In general, our policy around this type of reports is that if the issue is in a released LTS kernel, we will wait for a fix upstream, and if the issue is still in our queues, we will simply drop the patch from the queue. >This patch fixes a really quite serious vulnerability that allows an >unprivileged process to allocate arbitrary, unreclaimable (i.e. OOMK cannot >save you) memory. > >Allow me to assess the validity of this report _before_ dropping things >from queues perhaps? :) No disagreement that this would have been better - in this case it was timing as the releases were about to happen the following day, so the safest choice was to drop it while we figure it out. >It was sent late on Friday in a week that I was ill and it's Saturday >pre-LPC, so that's hardly a timeframe that I could reasonably have replied. Keep in mind that our release cycles are fairly short, so this shouldn't be too big of a deal? We will generally go for the safe option of dropping a commit that introduces a regression as it's fairly easy to queue it back up very soon after a diagnosis/fix shows up. -- Thanks, Sasha